The present invention is directed to apparatus for generating at least one moving object across a video display screen where wraparound of the object is avoided. More specifically, such wraparound occurs where an object is to be displayed near the edge of the screen (but necessarily only a portion of it can be displayed) and unless precautions are taken both portions of the object may theoretically be displayed one portion at one edge and one portion at the opposite edge.
In order to remedy the foregoing in a video game, where for example, a PT boat is being moved across the screen, one solution has been a logic unit controlling the game which outputs two binary digits or bits which provide four logical states; viz, display the left side of the screen, display the right side, display both, or lastly display neither meaning blank.
Another technique, which is somewhat difficult in application required the use of nine bits of horizontal counter range. This was cumbersome since the efficiency of binary architecture dictates that a four to eight bit unit of incremental change be used.
In addition, with regard to the above-mentioned two bit decoding scheme even the addition of one extra required bit of information may either significantly increase the overall cost of the binary logic required for a video game or alternatively signficantly reduce its flexibility of operation.